The present invention relates generally to a semiconductor device, and more particularly, to a structure of bonding pads and method for fabricating thereof.
A conventional semiconductor device, shown in Japanese patent publication Kokai 2000-183104, includes bonding pads having two layers. One of the layers is made of tungsten, titanium or an alloy of tungsten and titanium, while the other layer is made of an aluminum system alloy including copper. Namely, such conventional bonding pads are made of metal layers.
According to the above-described conventional semiconductor device, mechanical shock or impact is transferred to the bonding pads and a circuitry arranged under the bonding pads in a wire-bonding process. The bonding pads and circuitry may be damaged in some cases. As a result, the reliability and yield of semiconductor devices are lowered.
Accordingly, it is an object of the present invention to provide a semiconductor device in which a bonding pad and circuitry arranged under the bonding pad are prevented from being damaged.
Another object of the present invention to provide a method for fabricating a semiconductor device in order that a bonding pad and circuitry arranged under the bonding pad are prevented from being damaged.
Additional objects, advantages and novel features of the present invention will be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
According to a first aspect of the present invention, a semiconductor device includes a substrate; a metal layer formed on the substrate; an insulating layer, which is formed on the metal layer and is provided with a via-hole through it; and a bonding pad formed above the via-hole. The bonding pad comprises an inner portion arranged in the via-hole and an outer portion arranged above the via-hole. The boding pad is made of a conductive resin having a shock-absorbing characteristic.
According to a second aspect of the present invention, a method for fabricating a semiconductor device including: providing a substrate; forming a metal layer on the substrate; forming an insulating layer on the metal layer; forming a via-hole through the insulating layer; providing a conductive resin which has a shock absorbing characteristic; and filling the via-hole with a conductive resin to form an inner portion of a bonding pad. An outer portion of the bonding pad is formed with the conductive resin above the via-hole.
The bonding pad may be formed by dropping or dripping a liquid state of conductive resin into the via-hole in order that the conductive resin is filled in the vial hold for the inner portion and also overflow from the via-hole for the outer portion.
The semiconductor device may further include an enclosure formed around the via-hole on the insulating layer to define a peripheral boundary of the outer portion of the bonding pad. The enclosure can be formed on the insulating layer by the steps of: providing an insulating sheet, which is to be functioning as the enclosure; forming an opening on the insulating sheet at an area to be corresponding to the via-hole; and placing and adhering the insulating sheet with the opening onto the insulating layer.
The bonding pad may be formed by the steps of: providing a solid state conductive resin; placing the solid state conductive resin over the via-hole; and heating the conductive resin in order to melt the material and fill into the via-hole to form the inner portion, while a part of the conductive resin remaining on a protecting layer forms an outer portion.